Mode of constructing double-centered joints



UNITED sTATEs PATENT OFFICE.

EGBERT HEDGE, OF HARTFORD,- CONNECTIOUT.

MODE OF CONSTRUCTING DOUBLE-GENTERED JOINTS, BUTTS, OR HING'ES.

Specificaton of Letters Patent No. 473, dated November 23, 1837.

To all 'whom it may Gomera:

Be it known that I, EGBERT HEDGE, of Hartford, in the county of I'Iartford and State of Connectiout, have invented a new and useful Improvement in Double-Centered Joints, Butts, or IfIinges;V and I do hereby declare that the following-is a full and exact description.

The nature of my invention consists inso modifying the double centered joint, butt or hinge, by means of cogs or teeth, as to reduce its action in turning upon or around its centers to the accuracy and certainty of single centered joints.

To enable others skilled in the art to make and use my invention, I will proceed to describe its construction and operation.

As the purposes for which double centered joints have heretofore been used, or may hereafter, with my improvement be more advantageously used, are indefinite, I will describe it as it may be used for card table butts, (double centered joints having been long known and extensively used, for this purpose,) and as a joint forcarpenters, rules, 'for which purpose it has been more recently used. The latter, being the purpose for which I intend using it, in my own business, will require the more particular description. I do not,however, intend by thus descrbing it, to relinquish my claim to the improvement, if used for other purposes.

The principle defect of the double centered joint, as heretofore used, consists in the va-gue and uncertain manner of their turning on their Centers, in the process of opening and closing. For an instance, in opening the joint, ifV the turning upon one of its centers, happens, from any cause, to be easier than that of the other, it'will turn on its easiest center, until it meets a barrier, before .the turning upon its other center commences. To remove this uncertainty, I make use of cogs or teeth, formed on the quarter circular parts of the joints, shown at c, c, Figures 1, 2, 3 and 4, of the accompanying .drawing When intended for a card table butt, it usually consists of three distinct parts, viz: two equally shaped, but opposite parts or legs, a, a, Figs. 3 and 4, (on which the teeth are formed,) with countersunk holes, to receive the screws, by which it is attached to the leaves of the table.

T hese two parts are connected by a third plece, Z), Flg. 3, by means of two rivetsjpassmg through them. These rivetspalso serve as Centers, around which, the two firstnamed parts turn. Divested ofthe teeth, theabove described, would be precisely like the .com-F mon card table butt.

I usually construct Vit of four essential parts,

When used for thev mam, or center joint, for'carpenters rules,

or plates, connected together by two rivets.

Two of the plates, called middle plates, on which the teeth are formed, are shaped as represented at a, a, Fig.. 1. plates, shaped as at b, Fig.. 1, (or'ofV any other convenient shape,) calledthe voutside plates, are placed, one on each side of .the middle vplates,'the rivets, passing through the two middle plates, to interlock, orengage w1th each other. The teeth, thus engaged, compel the joint, in the process ofV opening and closing, to turn at all times equally upon each center, (which ,centers,' are the two connecting rivets,) and alsokeep the parts of the joint in their dueposition,

when the joint is at rest, either opened orV closed, the teeth being never disengaged. This joint I usually attach to'the vrule, by inserting the parts of the middle plates a, a, Fig. 2, which project from the outside plates, in grooves formed in the legs of the rule, the

ends of the legs being formed to fit to the' outside plates. VVhen inserted, I confine them in their places, by rivets, passing through the legs of the rule, and the middle When used for 'the small joints, in four fold rules, they are usually constructed like the above described, for card table butts, only of the proper dimensions to fit the place in which they serve;v

What I claim as my invention, and vdesire to secure by Letters Patent, is

The use of cogs or teeth, in double centered joints, to insure the accurate and equal turning upon each center, in the process of opening and 'closing the joint, and to keepV theparts ofthe joint in their due positions when at rest, either Vclosed 'or .opened,V as above' described. i EGBERT HEDGE. Witnesses:

MELVIN COPELAND, ENooH GAINES.

i The other 'two j V` i the corresponding holes, bring the teeth of 

